The invention is directed to a measuring device for an optical medium upon employment of two transmitters that can be coupled to the optical medium at both sides thereof.
A measuring device of this type is disclosed by German Published Application 38 28 604, corresponding to pending U.S. Ser. No. 394,114, now U.S. Pat. No. 5,078,489, filed Aug. 15, 1989 and by U.S. Pat. No. 4,652,123, both incorporated herein, whereby the measuring principle shall again be set forth in brief below with reference to FIG. 1.
An optical medium OM in, for example, the form of a splice location, of a coupler, of a light waveguide with a longer length, of a light waveguide cable, or of some other passive optical component, should have its transmission properties measured, whereby it is particularly the attenuation that is of interest. For this purpose, two optical transmitters SE1 and SE2 are provided, these being arranged at both sides of the optical medium (unit under test) OM and being in communication with this optical medium via light waveguides LW1 and LW2. When the optical medium itself is already a light waveguide, or contains such a light waveguide, of course, the respective light waveguide ends of the optical medium can be directly co-employed as light waveguides LW1 and LW2. A respective receiver EM1 and EM2 is shown at each of the two sides of the optical medium OM. These receivers are designed such that they can accept signals both from the transmitter SE1 as well as from the transmitter SE2. The measuring procedures sequence in the following way in detail:
Transmitter SE1 activated--Output Power P100 PA0 Transmitter SE2 Activated--Output Power P200
a) Receiver EM1 coupled--Measurement of the Reception Level P101 PA1 b) Receiver EM2 coupled--Measurement of the Reception Level P102 PA1 a) Receiver EM1 coupled--Measurement of the Reception Level P201 PA1 b) Receiver EM2 coupled--Measurement of the Reception Level P202.
In the way disclosed in greater detail in German Published Application 38 28 604 incorporated herein, the attenuation of the optical medium OM can be identified in an exact way from the measured values P101, P102, P201, and P202 received in this manner. In detail, the coupling of the respective measurement transmitter SE1 and SE2 occurs either via optical couplers, or these transmitters--when a through line is not involved--are directly connected to the face end of the light waveguides LW1 and LW2. By contrast, the receivers EM1 and EM2 are always connected to the light waveguides LW1 and LW2 via couplers, preferably flectional couplers.